Tag Archives: Dutch Elm Disease

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10 Alpharetta Tree Diseases – Identification & Treatment

Tree diseases cause severe damage to branches foliage and fruit appearing as scabs die back and mushroom conks

Need help identifying a potential tree disease? Recognizing when your tree is diseased will help you take prompt action to prune, treat, or call in an arborist or professional to halt the disease’s progression.

72tree.com gathered the following information to help you identify tree diseases and how to effectively treat your tree to prevent further decline or death.

What Does a Diseased Tree Look Like?

Diseased trees can physically manifest their ailments in multiple ways. Some common indicators of a diseased tree include:

• Low hanging dead or dying branches (lacking bark and have no leaves)
• Dropping dying or dead branches
• Weak, V-shaped branch unions, where two branches have grown together
• An excessively thick or dense canopy that could easily break
• Excessive wilting
• Leaf problems (spots, holes, odd colored, or deformed leaves)
• Fuzzy or moldy patches
• Water sprouts (water shoots) grow on the trunk or roots

Note: An alarming sign of advanced tree disease is when a tree starts to lean. This is an urgent problem requiring immediate professional attention.

Common Tree Diseases

The following tree diseases and their host species may require a professional assessment to determine an effective treatment plan. For an arborist in Alpharetta, we can help, or find a local arborist by visiting treesaregood.org/findanarborist. A third option is to collect samples of the tree and have them analyzed at your local university extension.

Consider the following 10 tree diseases:

1. Dutch Elm Disease (DED) (Ophiostoma ulmi) – A fungal disease that infects elm trees, causes rapid decline and death and is spread by bark beetles.

Tree diseases cause severe damage to branches foliage and fruit like Dutch elm disease

Treatment: When caught early, DED infections can be pruned out, and the tree can be protected by fungicides. Several DED-resistant elm varieties are available.

2. Oak Wilt (Ceratocystis fagacearum) – A fungal disease that affects oak trees and is spread through root grafts and sap-feeding, boring beetles.

Treatment: Trees infected with or have died from oak wilt should be completely removed, properly treated, and destroyed to prevent spore mat development. These treatments may include debarking, chipping or splitting, drying, and burning the wood.

3. Apple Scab (Venturia inaequalis) – A fungal disease that affects apple trees and causes leaf spotting and premature leaf drop.

Treatment: Scab control for edible apple and crabapple trees includes captan, lime-sulfur, and powdered or wettable sulfur applications.

Tree diseases cause severe damage to branches foliage and fruit like apple scab

4. Pine Wilt Disease (Bursaphelenchus xylophilus) – A bacterial disease that affects pine trees and is spread by pinewood nematodes and pine sawyer beetles.

Treatment: Once infected with pinewood nematodes, pesticides are no longer effective. Once a tree is infected, there is no cure for pine wilt, and dead trees left in the landscape become sources of nematodes and pine sawyer beetles. Diseased trees should be destroyed by burning, chipping, or burying.

5. Chestnut Blight (Cryphonectria parasitica) – A fungal disease affecting chestnut trees, causing cankers on the trunk and branches.

Treatment: Chestnut trees with blight cankers can be treated and often cured with mud packs applied to each canker.

6. Black Knot (Dibotryon morbosum) – A fungal disease that affects cherry and plum trees, causing black, warty growths on the branches.

Tree diseases cause severe damage to branches foliage and fruit like black knot

Treatment: Black knot can be controlled by removing all knots and swellings by pruning 3 to 4 inches below the knot during the dormant season. Where infections occur on larger branches, excise infected tissue down to healthy wood.

7. Cedar Apple Rust (Gymnosporangium juniperi-virginianae) – A fungal disease affecting apple trees but is spread by cedar trees.

Treatment: Fungicides with Myclobutanil are most effective in preventing rust. Spray trees when buds first emerge until spring weather becomes consistently warm and dry.

Tip: Fungicides are only effective when applied before leaf spots or fruit infections appear.

8. Fire Blight (Erwinia amylovora) – A bacterial disease affecting apple and pear trees, causing wilting and blackening of the branches. There is no cure for fire blight, only control.

Treatment: Once an infected tree is removed, the fire blight bacteria are also removed. You can safely plant another apple or pear tree in its place (choose a fire blight-resistant variety).

9. Verticillium Wilt (Verticillium dahliae and Verticillium albo-atrum) – A fungal disease that affects a wide range of trees and causes foliage chlorosis and wilting. There is no effective treatment for verticillium wilt.

Tree diseases cause severe damage to branches foliage and fruit like verticillium wilt

Treatment: Prune out affected branches and dispose of them immediately. Do not use infected wood for chips for landscape mulch.

Tip: Sanitize all pruning equipment before moving to another tree to prevent the spreading of the disease.

10. Sudden Oak Death (SOD) (Phytophthora ramorum) – A fungal disease affecting oak trees, causing leaf spots, cankers, and rapid death.

Treatment: Reliant Systemic Fungicide is a phosphonate compound injected into the tree or mixed with a surfactant and sprayed on the trunk for absorption through its bark.

Note: This treatment is not a cure but can help protect trees from infection and effectively suppress disease progression in early infection stages.

Tree Diseases

In this article, you discovered information to help you identify and treat several tree diseases before they cause your tree’s rapid decline or death.

Knowing how to identify when your tree is diseased will help you spring into action with effective treatments or get professional help.

Your inability to detect or identify when your tree is diseased can lead to rapid decline, death, and catastrophic personal or structural damage when it collapses or falls on your property.


Image credit: mndaily.com
Image credit: web.extension.illinois.edu
Image credit: hortnews.extension.iastate.edu

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Elm Tree Diseases Symptoms and Treatments

American elm tree or ulmus americana

Prevent your elm tree from rapid decline and death due to disease. Knowing how to identify and treat elm tree diseases will help you keep them healthy and thriving.

72tree.com assembled the following elm tree disease information, symptoms, and what treatments can help you save them from decline and death.

Elm Tree Disease

The following are some of the more common diseases that affect elm trees (Ulmus) and the treatments used to stop them from killing the trees.

Dutch Elm Disease (DED)

This disease was introduced to the U.S. in the 1930s and has since decimated the American elm (Ulmus americana) population. All native elms and European elms are susceptible, and the disease, 90 years later, still poses a significant threat.

Dutch elm disease is caused by two closely related fungi species (Ophiostoma ulmi and Ophiostoma novo-ulmi), the latter being responsible for most of the disease’s devastation. This fungus species attacks the elm’s vascular system. The tree, in turn, tries to stop the spread of the fungus by producing tyloses (plug-like structures) that block the flow of water and nutrients, contributing to the tree’s demise.

Dutch Elm Disease Symptoms Include:

• Premature leaf drop.

• The first symptom in infected trees usually appears as a small yellow or brown wilting area of foliage referred to as “flagging,” often starting at the edge of the crown.

• Wilting rapidly spreads inward toward the trunk.

• Leaves wilt, yellow, and eventually turn brown.

• Branch death.

• Brown streaking in sapwood (revealed by removing the bark or by cutting a cross-section of the dying branch).

This disease advances very fast. Depending on the health of the tree and time of infection, Dutch elm disease can lead a healthy adult elm tree to its death in a single growing season.

Dutch elm disease symptoms include fast foliage chlorosis and death

Dutch Elm Disease Treatment:

• Extensive pruning of infected areas.

• Remove severely infected trees.

• Burn or bury all infected wood (kills beetle larvae).

• Sever root graphs (connections) with neighboring trees.

• Preemptively treat uninfected trees with pesticides targeting elm bark beetles.

• Sterilize all pruning and maintenance equipment and materials after contact with infected trees.
• Create bait trees by treating them with cacodylic acid, killing the tree, and luring the fungus carrying beetles (this method suppresses brood production, making the beetle more manageable).

• Apply anti-fungal sprays to areas where infected trees are or have been.

• Plant DED resistant cultivars.

Note: If Dutch elm disease is caught early enough, extensive pruning may save the tree.

Multiple DED-resistant American elms and hybrid elm species are currently available and being developed. Some disease-resistant cultivars include:

• Accolade

• Cathedral

• Discovert

• Homestead

• Jefferson

• Morton Glossy

• Morton Stalwart

• New Horizon

• Pathfinder

• Pioneer

• Prospector

• Regal

• Valley Forge

Tip: Hire an ISA certified arborist to accompany or supervise all DED treatment strategies.

Elm Yellows (Formerly Elm Phloem Necrosis)

Elm yellows or phloem necrosis is a fast moving tree disease

Elm yellows is an aggressive disease affecting elm trees that is spread via root grafts or leafhoppers. Also known as elm phloem necrosis, the disease is fast-moving, has no cure, and occurs principally in the eastern United States and southern Ontario.

This disease is caused by phytoplasmas that infect the tree’s phloem (inner bark). This infection quickly kills the tree’s phloem, girdling the tree and stopping its flow of water and nutrients.

Elm Yellows Symptoms Include:

• Root debilitation (root hairs die).

• The phytoplasma infection kills the phloem (causing it to change color and take on a wintergreen-like smell.

• Inner bark tissues exhibit butterscotch or light brown discoloration, usually in streaks.

• The crown will turn yellow and droop all at once.

• Leaf drop and death of branches.

Inner bark tissue discoloration may occur in branches, twigs, and the trunk on DED infected trees, where discoloration caused by elm yellows is more commonly found in the trunk.

Elm yellows symptoms can appear any time during the summer but are most common in mid-to late-summer.

Elm Yellows Disease Treatment:

• There is no cure for this disease. Once a tree exhibits signs of elm yellows, it is highly recommended to remove and destroy the tree. Thus, eliminating inoculum sources from the area.

• Thorough root removal after felling an infected tree.

• Control or management of phloem-feeding insects like leafhoppers and spittlebugs.

• Topical application of pesticides to deter insect feeding.

• Apply anti-fungal sprays to areas where infected trees are or have been.

Plant Asian and European elm species in areas where elm yellows is present. These cultivars exhibit resistance to this disease.

Note: Elm yellows does not move into new areas as quickly as Dutch elm disease, providing a larger window for infected tree removal, preventive treatments, and containment.

Laetiporus root rot (formerly Polyporus sulfureus)

As elm trees age, the damage inflicted by butt and root rot fungi can severely compromise their structural stability. Failure eventually occurs during strong winds or severe weather, often without warning, resulting in severe property or physical damage. Root and butt rot can be caused by one of many wood-decaying fungal pathogens, but one of the more commonly occurring in elm trees is Laetiporus sulphureus.

Laetiporus Root Rot Symptoms Include:

• Canopy dieback.

• Stunted shoots.

• Undersized or pale-colored foliage.

• Premature fall color change

• Clusters of yellow to salmon to orange, shelf-like fruiting structures (conks) that turn white with age form in summer or autumn months on the trunk near the ground and fall off during the winter.

• The conk’s underside has tiny pores in which millions of spores are formed.

• New conks form in the following summer and autumn months. The bark where the fruiting structures form will be slightly depressed and often cracked.

Laetiporus root rot kills elm trees by weakening roots near the root collar

Root and butt rot fungi damage may only be exposed when trees suffer windthrow or windsnap during strong winds or severe weather. In some cases, Root and butt rot symptoms are present but provide little to no information on the depth of decay in the roots and lower trunk.

Laetiporus Root Rot Treatment:

• Root rot, in nearly all instances, is a case for immediate tree removal. Especially when fruiting structures are present at the trunk base or on the root flare.

• Hire an ISA certified arborist to evaluate the infected tree and recommend a course of action.

Note: Tree root diseases can be best controlled by preventive measures. When planting new elm trees, select disease-resistant cultivars, only plant in well-drained soil, and avoid overwatering. Chemicals, like chloropicrin or methyl bromide, don’t cure the disease but can reduce the level of the infection. Such fumigants work best when applied in and around the base of an infected tree or in the hole left behind after tree removal.

What is Killing My Elm Trees?

In this article, you discovered information on some of the more deadly elm tree diseases, the signs they display, and how to treat or control them.

Knowing how to recognize and treat elm tree diseases can help you catch and treat a disease early enough to potentially save your tree.

Ignoring the signs of a diseased elm tree can result in catastrophic damages when that tree falls on your home or causes personal injuries.